About 20 years ago I had a field methods geology course for grad tudents that I was team teaching. We ran into a bunch of these "Roswell Creationists" who were involved in collecting some fossil reptiles (NOT able to recall the ages, but they were NOT dinosaurs, so maybe they were Miocene). So, if they wanted to even consdier C14 in the future, the samples were invalid because they were already converted to a silica rock and were NOT a bone .
I don't know whether they found any "Soft tissue " but I doubt it because the method of extracting oft tissues involeves chemically eroding the surrounding rock that contains it.
They were cleaning their samples within a large bucket with lots of detergents and water. One of my students asked them if they were going to do any contextual stratigraphy or dating. She got a really
puzzled look at the word "Contextual". Also, we had a great teaching moment because we had the students go over the field methods used by the other batch (they might have been from any number of the Creationist museums that are around the US).
The first thing all the students picked up on was the possible "contamination" of the samples by the detergent itself. We didn't think they were going to do any C14 then but lots of the C14 samples that are being done NOWADAYS, are from old samples in collections.
My one partner (who IS a paleontologist) had noted that several of the samples that were recently sent to the tree ring lab at U of Arizona, were reported as "Shellacked' and he wondered whether any of them were washed "clean" using non-Di water and detergents or soaps.
When **** is that old, it only takes the presence of a very few atoms of C14 to actually give a bogus date. There SHOULD BE , no C14 there at all, and the fact that someone finds it should NOT be ascribed to an IN SITU condition of the sample itself.